Carburetor



Dec. 24, 1935. E. F. GEIGER CARBURETOR Filed Apfil 8, 1952 INVENTOZ Patented Dec. 24, 1935 UNITED. STATES PATENT OFFlC'E 2,025,504 cARBURE'roB.

Edward F. Geiger, Chicago, Ill. Application April 8, 1932, Serial No. 603,919

8 Claims. (01. 261-34) This invention relates to improvements in carburetors and in general the invention has for its objects the provision of a carburetor of comparatively simple construction which in, operation will provide a-relatively richmixture under wide open throttle conditions and a more economical and lean mixture under relatively closed throttleconditions and at times when the engine is running under light loads.

A further object of the present invention resides in the provision of. a carburetor which will efliciently perform its functions and in which auxiliary air valves and many other movable parts are dispensed with.

A' further object of the present invention'residesin the provision of a novel means for maintaining the proper proportions of air and fuel when the throttle valve is suddenly opened. Further and other objects of the prwent invention will be hereinafter set forth in the accompanying specification and claims and shown in the drawing, which by way of illustration shows what I now consider to be preferred embodiments of the invention.

In the drawing:

Figure 1 shows a vertical sectional view of the carburetor;

Fig. 2 is a detail horlzontal sectional view taken substantially on line 2-2 of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is a sectional view taken substantially on line 3-3 of Fig. 1 and looking in the direction of the arrows.

The carburetor comprises a casing l8 having an air inlet l2, air choke valve M, mixture outlet l8, throttle valve l8 and the usual constant level fuel supply reservoir 28 which is kept supplied with fuel through a pipe 22. Disposed in the casing l8 adjacent the throttle valve l8 and onthe intake side thereof is a part 24 which, with the casing l8, provides'a Venturi like passage 28 on one side of part 28. Passing through part 28 and parallel to theVenturi passage 28 but separate from the-passage 28 is a second Venturi shaped passage 28. The arrangement is such that one venturl is comparatively larger than the other, venturi 28 being larger than venturi 28.

In one embodiment of the present invention the relative proportions of these two venturis have been made in the ratio of four to one. The part 28 extends up in proximity to the throttle valve and has a surface 38 which is are shaped so as to form with the throttle valve stem, or shaft II, a barrier to the flow ofair or fuel mix-' ture between the outlet sides of Venturi passages 28 and 28 when a relative difference in pressure I exists in the outlets of thesepassages.

Disposed in the throat of Venturi passage 28 is a fuel nozzle .32 which through a common fuel supply passage 34 and fuel metering arrangement or orifice devices 38 and 38 communicates with the constant level fuel reservoir 2-0.

Extending up into the throat of venturi 28 is a fuel nozzle 48 which is in communication with the common fuel supply passage 34,.througha fuel metering arrangement or orifice device 42.

A conduit 44 is shown adapted to conduct air from ahead of the Venturi section 28 into the nozzle 48 for bleeding air into the fuel below the normal fuel level. A like conduit may be employed in conjunction with nozzle 32 for the same purpose. The fuel metering arrangement 38 is shown as a plug or head having a calibrated passage for the I fuel, but if desired an adjustable needle valve 'may be substituted for this fixed orifice fuel metering 2o device. l v I v The fuel metering device 38 comprises a cylindrical chamber 38 (see Fig. 2) having one or more nozzle like entrances 38a for fuel and a. fuel .out-

let 38a. The fuel entrance passages 38a enter the chamber 38 substantially tangentially to its cylindrical'surface and the fuel outlet passage 38a leaves the chamber 39 substantially centrally with respect to its medial axis. When fuel flows through this device the nozzles 38a cause .Serial No. 384,774, filed .August 9, 1929 .which matured into Patent 1,865,851 granted July 5, 1932.

38 and 38 acting in conjunction with each other,

in certain cases it may be desirable to entirely dispense with one or the other of these metering devices and to use either 38 or 38 alone to meter .the fuel entering the fuel supply conduit.-

In carburetor practice it has been'found that when the throttle valve is suddenly opened from 60 a nearly closed position the flow of air reaches maximum proportions almost instantly, but the flow of fuel lags behind the air flow and builds up to its maximum proportions slowly. This for a moment forms a weakfuel mixture and may While I have shown the fuel metering devices established through the regular passages.

cause the engine to stall or at best it causes the engine to respond slowly to the opening of the throttle. To counteract this effect an accelerating pump and valving device are provided that function only on rapid opening movement of the throttle and operate to instantly force an extra supply of fuel to the fuel nozzles to compensate for the first rush of air through the carburetor upon sudden opening of the throttle. This device also for a moment maintains an extra passage for fuel while normal fuel flow is being This accelerating pump and its associated devices will now be described. Referring to the drawing, 68 is a cylinder containing pistons 62 and 64. The cylinder 60 communicates with the main fuel passage 84 through ranged to engage a lever 12 which cooperateswith camming devices 14 attached to the throttle valve stem l8. With this arrangement an opening movement of the throttle will positivelytforce piston 62 downward against the force of the spring I6. This spring I6 presses the piston 52 upward and tends to keep its stem head 18 in engagement withthe lever-|2. A'bypass 56 is also provided from the cylinder 10 into the top of the float chamber. The .action of this arrangement is as follows: denly opened the piston 52 is positively forced downward at a rate which is faster than the fuel can bypass piston 54 through the calibrated bypass passage 66 and the m'draulicpressure produced in the fuel between the pistons 52 and 54 forces piston 54 downward. This downward movement of 54 pushes stop 64 out of passage 62 and through the calibrated orifice 68 forces fuel into the main fuel passage 34. The pressure which is available for forcing the fuel through passage 62 depends upon the size ofthe passage 58. The distance the piston 64 is forced -down-.

ward depends upon the degree of opening movement of throttle. valve II. when the throttle opening movement ceases the spring 66 will force piston 64 back to its upward position but the movement of this. piston will be delayed due to the necessity of the fuel between the two pistons 52 and 64 bypassing piston 64 through passage 68. While this upward movement of-54 is taking place passage 62 remains open allowing extra fuel to flow'from chamber 20 through passages 58,

62 and 88 and intopassa'ge 64, thus augmenting the fuel supply normally derived through the metering heads 86 and 88.

It has been previously explained that venturi j 28 is-smaller than venturi 26 and in one embodiment of the present invention has been made about one quarter the size of venturi 26. When the throttle l8 isv slightly opened, the throttle,

equal the volume of air passing through-venturi 26. However, the pressure upon the outlet of nozzle 40 will be relatively lower than the pressure of the outlet at nozzle 82 on account of the When the throttle valve I8 is sud-- directly with the source of fuel supply.

relative size of the two venturis. The predominating supply of fuel will then pass through 40 and the flow through this nozzle can be set for a lean economical mixture by means of fuel metering device 42. when the throttle is in wide open 5 position the manifold pressure is practically applied without restriction directly to both venturis 26 and 28, and 26 being larger more air will fiow through 26 than through 28. In fact, practically four times as much'air will fiow with the four to 10 one area ratio of the two venturis. The suction at the outlet of nozzle 82 will then equal the suction at the top of nozzle 48 and a relatively rich mixture will be supplied because 82 contains no restriction and is a relatively larger tube than 40 15 which is restricted at 42.

At intermediate positions of the throttle intermediate results are obtained.

, It will be noted that the fiow through both of the nozzles 32 and 40 is controlled by the fuel 20 metering devices 36 and I8.- By properly proportioning and calibrating these fuel metering devices a proper fuel mixture can be obtained for all operating air speeds with open throttle. The

centrifugal metering head 88 permits the making 25 of a rich mixture at low air speeds and furnishes a less rich mixture proportionately as the air speed is increased. The rate of decrease in richness can be changed by changing the relative proportions of the passages 36 and 38 so as to 30 increase or decrease the proportion of fuel that fiows through the centrifugal head 38.

What I claim is: I

1. A carburetor having a throttle and fuel nozzle devices, means for supplying additional 35.

fuel to the fuel nozzle devices upon rapid accelerating opening movement of the throttle, said means comprising a common cylinder and a pair of pistons both slidably cooperating with said common cylinder for operation therein, one pis- 40 ton being positively operated by and upon a rapid opening movement of the throttle, the second piston having a bypass passage therethrough and being operated by hydraulic action from said first piston, a valve operated by said second piston 45 upon hydraulic operation of said second piston by said first piston, said valve upon opening movements delivering additional fuel to the aforesaid nozzle devices.

2. An accelerating fuel pump for a carburetor 50 comprising a cylinder, a piston therein positively operated in one direction by a throttle opening operation, a second piston slidably operating in the same cylinder with the aforesaid piston and spaced therefrom and adapted for hydraulic op- 55 eration by said first mentioned piston and spring biased towards the same, a fuel valve operated 'by said second piston when the latter is operated by the first mentioned piston, a bypass through said second piston and a calibrated fuel passage to 00 feed fuel from below said second mentioned piston for delivery through the aforesaid valve.

3. A carburetor provided with a pair of venturis and a fuel nozzle extending through the throat of each venturi, a fuel supply passage for both of 65 said nozzles, a fuel metering orifice intermediate one of said nozzles and said passage, and a plurality of fuel metering orifices leading from a source of fuel supply to said fuel supply passage,

one of said orifices leading to an accelerating 70 I pump, the other of said orifices communicating 4 4. A carburetor comprising a pair of separate venturis with a fuel nozzle extending to the throat of each venturi, a common throttling 75 venturis with a fuel nozzle extending to the throat of each venturi, a common throttling means for controlling mixture flow through both venturis, common fuel metering means for controlling at all times and under all running conditions all fuel flow to all nwzles under the resultant suction developed at the throats of the separate venturis, and means for temporarily augmenting the amount of fuel supplied to the fuel nozzles upon sudden opening of the throttle.

5. An accelerating pump for a carburetor with a fuel reservoir, a cylinder, a piston positively operated therein in one direction by a throttle opening operation, a second piston in said cylinder adapted for hydraulic operation by said first mentioned piston and spring biased toward the same, a bypass through said second men-' tioned piston, a second bypass affording communication between the cylinder at a point below the second mentioned piston and the fuel reservoir, a fuel valve operated by said second mentioned piston when the latter is operated by the first mentioned piston to provide delivery of supplemental fuel to a fuel-passage beyond the valve, said fuel delivery of supplemental fuel being effected at the pressure existing in the cylaugmenting the 3 inder between the bypass through the second piston and the second bypass to the fuel reservoir.

'1. A carburetor comprising a pair of separate venturis with a fuel throat of each venturl, a common throttling means for controlling mixture flow through both venturis, and common fuel metering means for controlling at all times fuel flow to all nozzles under the resultant suction developed at the 10 throats of the separate venturis, said common fuel metering means including two calibrated ori- ,fices extending to a fuel reservoir with one oriiice comprising a centrifugal fuel flow metering device to cause the fuel flow to increase at a 15 lesser rate than the increase would be through a simple orifice as suction is increased.

8. A carburetor comprising a pair of separate venturis, a common throttling means for com trolling mixture flow through both venturis, a 20 pair of fuel nozzles receiving fuel from a fuel passage for delivery to both venturis, one nozzle receiving fuelfiow from said passage through a metering orifice, common fuel metering means for controlling at all times and under all running conditions all fuel flow to all nozzles under the resultant suction developed at the throats of the separate venturis, said common fuel metering means metering the said fuel passage from a reservoir and including means to cause the fuel flow to increase at a less rate than the increase would be through a simple orifice as suction is increased and means for temporarily amount of fuel supplied to the passage and therethrough to the fuel nozzles upon sudden opening of the throttle.

, EDWARD I". carom.

nozzle extending to the 5 

